Swiss racer Jo "Seppi" Siffert, a two-time F1 winner with victories at Daytona, Sebring, and the Targa Florio, is best remembered as a colorful supporting character from an era gone by. But in the world of vintage watches, Siffert's name carries clout. The white-faced Heuer Autavia chronograph he wore—introduced in 1968 and known to horologists as simply "the Siffert"—has become one of the most desirable vintage chronographs available.

Most Autavias, including the Viceroy models sold for $88 as part of a cigarette promotion, sported black dials. But Siffert's distinctive 1163T model wore a white dial, blue accents, and a tachymeter bezel. Thanks to its rarity (around 1,000 1163Ts were produced) and motorsport connection, it became a cult classic after Siffert's death at Brands Hatch in 1971.

A man of modest means, Siffert famously supported his racing habit by selling Heuer watches to fellow drivers. It was part of a sponsorship deal that brand scion Jack Heuer remembers as "one of the best marketing moves I ever made, since it opened the door to the closed-off world of F1." (Siffert, heavily involved with Porsche, was also a natural salesman; Heuer recalls that, on the day they signed the contract, "he wouldn't let me go home until he sold me a Porsche 911.")

The Siffert Autavia originally sold for between $225 and $250, and a decade ago it could still be had for less than $1,000. A clean original on its Gay Frères "grains of rice" band can now command as much as $10,000, while the earliest versions—the so-called Chronomatics, featuring a unique dial script—can fetch up to $40,000. The model also appeals to those who can afford far more expensive watches: Jerry Seinfeld has been filmed wearing his own Siffert on multiple occasions.

Part of the draw is the unfakeable authenticity. "Chronograph enthusiasts are always looking for a genuine connection to racing," says Jeff Stein, creator of On the Dash, a site dedicated to vintage Heuers. "And the Siffert is one of the watches that the racers were wearing."